GENERAL PHYSIOLOGY. 59 



The indirect stimulation of the gastrocnemius. 



Observations. To mount the muscle- nerve preparation in 

 the myograph. Fix the femur in the clamp (Fig. 13-c); 

 place a piece of filter paper, wet with normal saline solu- 

 tion, upon the glass nerve support (s); lay the nerve upon 

 the support; make a longitudinal slit in the tendo 

 achillis, pass the hook of the muscle lever through the 

 slit and so adjust the height of the clamp as to bring the 

 lever into a horizontal position. 



FIG. 13. 



FIG. 13. 



Simple myograph, with a femur-clamp (c), and a glass 

 plate (s) for a nerve rest. 



a. Mechanical Stimulation. (1) Snip off with scissors the 

 central end of the sciatic nerve. If the muscle in- 

 stantly contracts, thereby lifting the lever, the ob- 

 server will know that his preparation is successful. 

 If it does not respond to the first stimulation it may 

 to a second or subsequent one. If it responds to 



